Amount Of Viable Myocardium Assessed By Combining 99mTc-MIBI SPECT And 18F-FDG PET Enable To Predict Left Ventricular Ejection Fraction Improvement And Left Ventricular Volume Reduction After Coronary Artery Bypass Surgery

Objective: To predict left ventricular ejection fraction(LVEF) improvement and LV volume reduction after Coronary Artery Bypass Graft(CABG) using the amount of viable myocardium, assessed by combining positron emission tomography(PET) and single-photon emission computed tomography(SPECT).Method: Thirty-nine patients with ischemic cardiomyopathy undergoing surgical revascularization were studied prospectively with 99mTc-sestamibi gated SPECT myocardial perfusion imaging(GSMPI) and 18F-FDG PET myocardial metabolic imaging to assess preoperative myocardial viability and GSMPI to assess myocardial perfusion 3-6 months after CABG in The Third Affiliated Hospital of Soochow University from December 1st, 2013 to December 1st, 2014. Improvement in LVEF at least 5% and reduction of LV volume at least 10% was considered significant. Predictors for LVEF improvement and LV volume reduction after CABG were analyzed.Result: After CABG, 17 and 26 of 39 coronary artery disease(CAD) patients exhibited LVEF improvement(≥5%) and the reduction in LV end-diastolic volume(EDV) or end-systolic volume(ESV)(≥10%), respectively. LVEF improved group has more viable segments(5.4±2.6 vs 2.5±1.8,P<0.05)and less scar segments(0.3±0.6 vs 1.6±2.5, P<0.05) than that of LVEF non-improved group. Similarly, the number of viable segments of the LV reduced group is higher than that of the non-reduced group(4.5±2.8 vs 2.4±1.5, P﹤0.05)and the number of scar segments of the reduced group is less than that of the non-reduced group(0.5±1.0 vs 2.1±3.0, P﹤0.05). Moreover, the amount of viable myocardium is the independent factor for predicting LVEF improvement(OR=2.507, P<0.05) and LV volume reduction(OR=1.953, P<0.05). Furthermore, the optimal threshold value for the amount of viable myocardium in predicting LVEF improvement and reduced LV volume was ≥4 and ≥3.Conclusion: The LVEF improved group and reduced group has more viable segments and less scar segments than that of the LVEF non-improved group and the non-reduced group, respectively. The number of viable segments per patient was directly related to LVEF improvement and reduction of LV volume after revascularization. The optimal threshold value for the amount of viable myocardium in predicting LVEF improvement and reduced LV volume was ≥4 and ≥3. The amount of viable myocardium assessed by combining GSMPI and FDG-PET before CABG can effectively predict LVEF improvement and LV volume reduction after CABG.